Table of Contents: July 2012

The pattern in the figure was produced by a colony of Argentine ants after one hour of exploration of an empty arena. Many ant species form similar dendritic patterns around their nests, but the patterns are invisible to the human eye as they are composed of extremely low concentrations of chemicals (pheromones). In this image, the structure of the trails and the intensity of pheromone marking are made visible from the positions of the ants. See Perna et al., doi:10.1371/journal.pcbi.1002592.